Hi, i'm sure this as been asked many times but i cannot find the answer through various posts. I am going to re-tile my bathroom with 30 x 60cm porcelain tiles. My bathroom is mainly studded walls and to take off the existing tiles i will cause too much damage to the walls so i wanted to tile over them. What is the best adhesive to use as they are big tiles and whats the best method to prep the walls prior to tiling?

You need to think very hard before tiling over tiles. I do bathrooms every week and would NEVER tile over as it is a recipe for disaster. How are you going to tile up to doors and windows?? It will be thicker than the architrave.

Old tiles are often not stuck and the extra weight will result in everything falling off!!

Have you tried removing the tiles?? I find tiles can be removed without excessive damage to the walls in say, 85% of cases.

Thanks plumbbob for the advice. I've decided to remove the old tiles but as thought i've damaged the plasterboard walls so i will need to replace them.

I am thinking of using Gran Fix Fastset Flexible cement based adhesive with their Acrylic Bond and Primer prior to tiling on all walls which are just plasterboard and plaster brick walls. Is this ok? Is a 3mm bed thickness good enough if i also back butter the tile and what size notched trowel do i need to use.

"I am thinking of using Gran Fix Fastset Flexible cement based adhesive with their Acrylic Bond and Primer prior to tiling on all walls which are just plasterboard and plaster brick walls. Is this ok?"

yes - though you don't normally need to prime new plasterboard if it hasn't been skimmed.

"Is a 3mm bed thickness good enough if i also back butter the tile and what size notched trowel do i need to use."

no - apply adhesive to the wall, not the tile unless the adhesive manufacturer suggest otherwise. i'd use at least a 6mm notched trowel though the manufacturers instructions should be followed.

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